function navi_initialization(){
  document.onkeydown = NavigateThrough;
}

function NavigateThrough(event){  
  try{
        event   = event || window.event;
    var object  = event.target || event.srcElement;
    var keyCode = event.keyCode;
    if(event.ctrlKey){
      if(object.tagName!="INPUT"&&object.tagName!="TEXTAREA"){
        var link=null;
        switch (keyCode){
          case 0x25:{
            link = document.getElementById ('PrevLink');
            break;
          }
          case 0x27:{
            link = document.getElementById ('NextLink');
            break;
          }
        }
        if (link && link.href) document.location = link.href;
      }
    }
  }catch(e){
    logging("Error NavigateThrough:"+e.message);
  }
}